Aside from its great sub-genres such as cyberpunk, space opera or lately steampunk, science fiction writing fulfills some interesting social needs as well as reflecting and predicting the dominant cultural and scientific attitudes of the day. William Gibson’s Neuromancer published in 1984, for example prefigured the idea not only of data structures that could be beautiful, autonomous security software and a transnational data network it actually coined the term cyberspace.
Sometimes science fiction has such a powerful influence its ideas enter the cultural mainstream HG Wells’ War of the Worlds or John Wyndhams’ Day of the Triffids for example have become accepted classics allowing them to escape the gravity of their immediate genre. Science fiction is used to voice our fears of technology and where it might lead us. It is used to imagine disastrous dystopian futures where nature has turned against humankind. John Christopher’s Death of Grass or Cormac McCarthy’s The Road could be seen in this light. They feature desperate journeys through a desolate landscape with protagonists threatened by predatory gangs. In fact some people consider parts of the bible to be post apocalyptic science fiction. The eternal intergalactic warring of Fallout, Halo or Star Wars would fit into this genre.
Our fears of the future are sometimes a direct response to political messages. This phenomenon is well understood in the light of the cold war, (see Alien, Godzilla or Invasion of the Bodysnatchers). More recently the hysteria whipped up in response to Islamic fundamentalism can be seen in the fear-of-the-enemy-within present in District 9 or Moon.
The other side of the SF coin usually shows utopian visions of a united, tolerant technologically advanced society. The Culture novels of Iain M Banks or Commonwealth series of Peter F Hamilton show a breadth of vision for future society that reflects globalisation and the movement of transnational capital.
At its best science fiction in literature, film or computer games imagines dramatic and revealing futures, often based in the far reaches of quantum physics (Alastair Reynolds is particularly well known for this) and offering colourful visions of future intergalactic society (Kim Stanley Robinson's work).
SF writers have come into their own as science and technology become driving forces in society. One of the questions they must continually answer is; how can human imagination keep pace with and make sense of technological change?
By fulfilling our atavistic need for compelling stories set in realistic and elaborately fashioned worlds, that's how. SF we love you.